In the related art, the Evolved Packet System (EPS) network does not provide the circuit switching service, so the network element Mobility Management Entity (MME) of the EPS network cannot support the sending of the common short message. Usually the Evolved Packet System network provides data services, such as downloading and uploading from/to the network, etc., and the circuit switching network provides services, such as voice communication, short message, etc. And the EPS network can provide the data service with a higher peak rate for the user, therefore many users using the data service usually register to the EPS network; however when enjoying the high-speed data service, these users need to receive the short message service, in order to meet this demand, the users registering to the EPS network are also required to register to the circuit switching network which provides the short message service at the same time, thus the process of sending the short message is that: a short message service center (SMS-SC) sends the short message to the Mobile Switching Center Gateway used for sending the short message (SMS-GMSC), and the SMS-GMSC inquires the service node information of the terminal, that is, the address of the Mobile Switching Center and the address of the mobility management unit, from a home subscriber information storage network element (HSS), sends the address to the Mobile Switching Center (MSC) after obtaining the address, and then the Mobile Switching Center sends it to the mobility management unit (MME), and finally the MME sends the short message to the terminal.
As shown in FIG. 1, after the users in the packet switching network also register to circuit switching network that can provide the short message service at the same time, the process of sending the short message includes that: the short message service center (SMS-SC) sends the short message to the Mobile Switching Center Gateway used for sending the short message (SMS-GMSC), and the SMS-GMSC inquires the routing information required for sending the short message, that is, the service node information of the terminal, that is, the address of the Mobile Switching Center (MSC) or the address of the Service GPRS Supporting Node (SGSN), from a home subscriber information storage network element (HSS/HLR), and sends the short message to the MSC or SGSN after obtaining the address, and then the MSC or the SGSN sends the short message to the terminal.
The network elements are introduced as follows:
the SMS-SC: configured to generate the short message contents to encapsulate into the short message data packet according to the short message protocol;
the SMS-GMSC: configured to receive the short message data packet sent by the SMS-SC; read the parameters in the short message data packet, and check the parameters; and inquiry the routing information of the terminal from the HSS (here the routing information refers to the identification or address of the MSC or SGSN by which the short message is sent);
the HSS/HLR: configured to store subscription information of every subscriber, and the service node information (for example, the identification or address of the service node providing service for the terminal (MSC or SGSN));
the MSC: a core network entity providing service for the terminal in the circuit switching network (the service includes sending the control signaling, the short message delivery, and the mobility management);
SGSN: a core network entity providing service for the terminal in the packet switching network (the service includes sending the control signaling, the short message delivery, and the mobility management).
The device trigger service is a kind of services that the server triggers the terminal to establish the connection with the server or report the service voluntarily. The realization way of the device trigger service is to send a non-access stratum (NAS) signaling or short message. In the device trigger service, an application server sends a trigger request to an Interworking functional unit (IWF), and the trigger request includes an identification of the terminal to be triggered; the IWF sends the identification of the terminal to the HSS or the HLR, to obtain information of a core network service node of the terminal (that is, the MSC or the SGSN) from the HSS or the HLR (the information includes the identification or the address of the service node, and the ability about whether the corresponding service node supports the NAS signaling to send the trigger message). The IWF determines which transmission mode is adopted according to the ability of the service node. When the service node does not support the transmission mode of NAS signaling, the IWF sends the trigger request received from the application server to the SMS-SC, that is, sends the trigger request to the terminal with the short message, and the identification of the service node here is the routing information required for sending the short message.